Grant Specific Permission By Scripting

[font="trebuchet ms"]Hello All,
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[font="trebuchet ms"]I need to grant access to:
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[font="trebuchet ms"]Account: NT Service\MpsSvc
[font="trebuchet ms"]Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Epoch
[font="trebuchet ms"]Permission: Query Value and Set Value
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[font="trebuchet ms"]I have already tried to use SetACL but it only accepts to use a SID instead the account name, and I could not fine the SID for this NT Service\MpsSvc since it is a service.
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[font="trebuchet ms"]Please, may anyone suggest something to grant this permission by scripting?
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[font="trebuchet ms"]Thank you
[font="trebuchet ms"]Rodolfo